FCGR2B and chronic myelogenous leukemia, BCR-ABL1 positive: In order to study FcγRIIb function in vivo, we applied both a Bcr-Abl transduction model combined with genetic receptor depletion (Fig. 3a, model A) as well as strongly reduced FcγRIIb expression mediated by shRNA using the transgenic SCLtTA/Bcr-Abl CML mouse model (Fig. 3a, model B).